BACKGROUND: Accurate and precise estimates of the incubation distribution of novel, emerging infectious diseases are vital to inform public health policy and to parameterize mathematical models. METHODS: We discuss and compare different methods of estimating the incubation distribution allowing for interval censoring of exposures, using data from the severe acute respiratory syndrome (SARS) epidemic in 2003 as an example. RESULTS: Combining data on unselected samples of 149 and 168 patients with defined exposure intervals from Toronto and Hong Kong, respectively, we estimated the mean and variance of the incubation period to be 5.1 day and 18.3 days and the 95th percentile to be 12.9 days. We conducted multiple linear regression on the log incubation times and found that incubation was significantly longer in Toronto than in Hong Kong and in older compared with younger patients, while it was significantly shorter in healthcare workers than in other patients. CONCLUSIONS: Our findings suggest subtle but important heterogeneities in the incubation period of SARS among different strata of patients. Robust estimation of the incubation period should be independently carried out in different settings and subgroups for novel human pathogens using valid statistical methods.
BACKGROUND: Accurate and precise estimates of the incubation distribution of novel, emerging infectious diseases are vital to inform public health policy and to parameterize mathematical models. METHODS: We discuss and compare different methods of estimating the incubation distribution allowing for interval censoring of exposures, using data from the severe acute respiratory syndrome (SARS) epidemic in 2003 as an example. RESULTS: Combining data on unselected samples of 149 and 168 patients with defined exposure intervals from Toronto and Hong Kong, respectively, we estimated the mean and variance of the incubation period to be 5.1 day and 18.3 days and the 95th percentile to be 12.9 days. We conducted multiple linear regression on the log incubation times and found that incubation was significantly longer in Toronto than in Hong Kong and in older compared with younger patients, while it was significantly shorter in healthcare workers than in other patients. CONCLUSIONS: Our findings suggest subtle but important heterogeneities in the incubation period of SARS among different strata of patients. Robust estimation of the incubation period should be independently carried out in different settings and subgroups for novel human pathogens using valid statistical methods.
Authors: Benjamin J Cowling; Lianmei Jin; Eric H Y Lau; Qiaohong Liao; Peng Wu; Hui Jiang; Tim K Tsang; Jiandong Zheng; Vicky J Fang; Zhaorui Chang; Michael Y Ni; Qian Zhang; Dennis K M Ip; Jianxing Yu; Yu Li; Liping Wang; Wenxiao Tu; Ling Meng; Joseph T Wu; Huiming Luo; Qun Li; Yuelong Shu; Zhongjie Li; Zijian Feng; Weizhong Yang; Yu Wang; Gabriel M Leung; Hongjie Yu Journal: Lancet Date: 2013-06-24 Impact factor: 79.321
Authors: Tom Jefferson; Chris B Del Mar; Liz Dooley; Eliana Ferroni; Lubna A Al-Ansary; Ghada A Bawazeer; Mieke L van Driel; Sreekumaran Nair; Mark A Jones; Sarah Thorning; John M Conly Journal: Cochrane Database Syst Rev Date: 2011-07-06
Authors: Jens W Levy; Benjamin J Cowling; James M Simmerman; Sonja J Olsen; Vicky J Fang; Piyarat Suntarattiwong; Richard G Jarman; Brendan Klick; Tawee Chotipitayasunondh Journal: Am J Epidemiol Date: 2013-04-28 Impact factor: 4.897
Authors: Victor Virlogeux; Vicky J Fang; Joseph T Wu; Lai-Ming Ho; J S Malik Peiris; Gabriel M Leung; Benjamin J Cowling Journal: Epidemiology Date: 2015-09 Impact factor: 4.822
Authors: Eric H Y Lau; C Agnes Hsiung; Benjamin J Cowling; Chang-Hsun Chen; Lai-Ming Ho; Thomas Tsang; Chiu-Wen Chang; Christl A Donnelly; Gabriel M Leung Journal: BMC Infect Dis Date: 2010-03-06 Impact factor: 3.090